Component

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A Component is like an empty canvas, where you can add polygons, references to other Components and ports (to connect to other components)

In gdsfactory all dimensions are in microns

Lets add a polygon

import gdsfactory as gf
from gdsfactory.generic_tech import get_generic_pdk

gf.config.rich_output()

PDK = get_generic_pdk()
PDK.activate()

# Create a blank component (essentially an empty GDS cell with some special features)
c = gf.Component("myComponent")

# Create and add a polygon from separate lists of x points and y points
# (Can also be added like [(x1,y1), (x2,y2), (x3,y3), ... ]
poly1 = c.add_polygon(
    [(-8, 6, 7, 9), (-6, 8, 17, 5)], layer=1
)  # GDS layers are tuples of ints (but if we use only one number it assumes the other number is 0)

# show it in matplotlib and KLayout (you need to have KLayout open and install gdsfactory from the git repo with make install)
c

2023-02-20 17:44:38.647 | INFO     | gdsfactory.config:<module>:50 - Load '/home/runner/work/gdsfactory/gdsfactory/gdsfactory' 6.43.1
2023-02-20 17:44:39.531 | INFO     | gdsfactory.technology.layer_views:__init__:785 - Importing LayerViews from YAML file: /home/runner/work/gdsfactory/gdsfactory/gdsfactory/generic_tech/layer_views.yaml.
2023-02-20 17:44:39.538 | INFO     | gdsfactory.pdk:activate:206 - 'generic' PDK is now active

myComponent: uid fca1ac2c, ports [], references [], 1 polygons

Exercise :

Make a component similar to the one above that has a second polygon in layer (1, 1)

c = gf.Component("myComponent2")
# Create some new geometry from the functions available in the geometry library
t = gf.components.text("Hello!")
r = gf.components.rectangle(size=[5, 10], layer=(2, 0))

# Add references to the new geometry to c, our blank component
text1 = c.add_ref(t)  # Add the text we created as a reference
# Using the << operator (identical to add_ref()), add the same geometry a second time
text2 = c << t
r = c << r  # Add the rectangle we created

# Now that the geometry has been added to "c", we can move everything around:
text1.movey(25)
text2.move([5, 30])
text2.rotate(45)
r.movex(-15)
r.movex(-15)

print(c)
c

myComponent2: uid 5bf5d22e, ports [], references ['text_1', 'text_2', 'rectangle_1'], 0 polygons

myComponent2: uid 5bf5d22e, ports [], references ['text_1', 'text_2', 'rectangle_1'], 0 polygons

Connect ports

Components can have a “Port” that allows you to connect ComponentReferences together like legos.

You can write a simple function to make a rectangular straight, assign ports to the ends, and then connect those rectangles together.

@gf.cell
def straight(length=10, width=1, layer=(1, 0)):
    WG = gf.Component()
    WG.add_polygon([(0, 0), (length, 0), (length, width), (0, width)], layer=layer)
    WG.add_port(
        name="o1", center=[0, width / 2], width=width, orientation=180, layer=layer
    )
    WG.add_port(
        name="o2", center=[length, width / 2], width=width, orientation=0, layer=layer
    )
    return WG


c = gf.Component("straights_not_connected")

wg1 = c << straight(length=6, width=2.5, layer=1)
wg2 = c << straight(length=11, width=2.5, layer=2)
wg3 = c << straight(length=15, width=2.5, layer=3)
wg2.movey(10).rotate(10)
wg3.movey(20).rotate(15)

c

straights_not_connected: uid 9d5f8d22, ports [], references ['straight_1', 'straight_2', 'straight_3'], 0 polygons

# Now we can connect everything together using the ports:

# Each straight has two ports: 'W0' and 'E0'.  These are arbitrary
# names defined in our straight() function above

# Let's keep wg1 in place on the bottom, and connect the other straights to it.
# To do that, on wg2 we'll grab the "W0" port and connect it to the "E0" on wg1:
wg2.connect("o1", wg1.ports["o2"])
# Next, on wg3 let's grab the "W0" port and connect it to the "E0" on wg2:
wg3.connect("o1", wg2.ports["o2"])

c

straights_not_connected: uid 9d5f8d22, ports [], references ['straight_1', 'straight_2', 'straight_3'], 0 polygons

c.add_port("o1", port=wg1.ports["o1"])
c.add_port("o2", port=wg3.ports["o2"])
c

straights_not_connected: uid 9d5f8d22, ports ['o1', 'o2'], references ['straight_1', 'straight_2', 'straight_3'], 0 polygons

As you can see the red labels are for the component ports while blue labels are for the sub-ports (children ports)

Move and rotate references

You can move, rotate, and reflect references to Components.

c = gf.Component("straights_connected")

wg1 = c << straight(length=1, layer=(1, 0))
wg2 = c << straight(length=2, layer=(2, 0))
wg3 = c << straight(length=3, layer=(3, 0))

# Create and add a polygon from separate lists of x points and y points
# e.g. [(x1, x2, x3, ...), (y1, y2, y3, ...)]
poly1 = c.add_polygon([(8, 6, 7, 9), (6, 8, 9, 5)], layer=(4, 0))

# Alternatively, create and add a polygon from a list of points
# e.g. [(x1,y1), (x2,y2), (x3,y3), ...] using the same function
poly2 = c.add_polygon([(0, 0), (1, 1), (1, 3), (-3, 3)], layer=(5, 0))

# Shift the first straight we created over by dx = 10, dy = 5
wg1.move([10, 5])

# Shift the second straight over by dx = 10, dy = 0
wg2.move(origin=[0, 0], destination=[10, 0])

# Shift the third straight over by dx = 0, dy = 4
wg3.move([1, 1], [5, 5], axis="y")

# Move "from" x=0 "to" x=10 (dx=10)
wg3.movex(0, 10)

c

straights_connected: uid b6ebee21, ports [], references ['straight_1', 'straight_2', 'straight_3'], 2 polygons

Ports

Your straights wg1/wg2/wg3 are references to other waveguide components.

If you want to add ports to the new Component c you can use add_port, where you can create a new port or use an reference an existing port from the underlying reference.

You can access the ports of a Component or ComponentReference

wg2.ports

{
    'o1': Port (name o1, center [10.   0.5], width 1, orientation 180.0, layer (2, 0), port_type optical),
    'o2': Port (name o2, center [12.   0.5], width 1, orientation 0.0, layer (2, 0), port_type optical)
}

References

Now that we have your component c is a multi-straight component, you can add references to that component in a new blank Component c2, then add two references and shift one to see the movement.

c2 = gf.Component("MultiMultiWaveguide")
wg1 = straight()
wg2 = straight(layer=(2, 0))
mwg1_ref = c2.add_ref(wg1)
mwg2_ref = c2.add_ref(wg2)
mwg2_ref.move(destination=[10, 10])
c2

MultiMultiWaveguide: uid 88e576b0, ports [], references ['straight_1', 'straight_2'], 0 polygons

# Like before, let's connect mwg1 and mwg2 together
mwg1_ref.connect(port="o2", destination=mwg2_ref.ports["o1"])
c2

MultiMultiWaveguide: uid 88e576b0, ports [], references ['straight_1', 'straight_2'], 0 polygons

Labels

You can add abstract GDS labels (annotate) to your Components, in order to record information directly into the final GDS file without putting any extra geometry onto any layer This label will display in a GDS viewer, but will not be rendered or printed like the polygons created by gf.components.text().

c2.add_label(text="First label", position=mwg1_ref.center)
c2.add_label(text="Second label", position=mwg2_ref.center)

# It's very useful for recording information about the devices or layout
c2.add_label(
    text=f"The x size of this\nlayout is {c2.xsize}",
    position=(c2.xmax, c2.ymax),
    layer=(10, 0),
)

# Again, note we have to write the GDS for it to be visible (view in KLayout)
c2.write_gds("MultiMultiWaveguideWithLabels.gds")
c2

2023-02-20 17:44:44.748 | INFO     | gdsfactory.component:_write_library:1704 - Wrote to 'MultiMultiWaveguideWithLabels.gds'

MultiMultiWaveguide: uid 88e576b0, ports [], references ['straight_1', 'straight_2'], 0 polygons

Boolean shapes

If you want to subtract one shape from another, merge two shapes, or perform an XOR on them, you can do that with the boolean() function.

The operation argument should be {not, and, or, xor, ‘A-B’, ‘B-A’, ‘A+B’}. Note that ‘A+B’ is equivalent to ‘or’, ‘A-B’ is equivalent to ‘not’, and ‘B-A’ is equivalent to ‘not’ with the operands switched

c = gf.Component()
e1 = c.add_ref(gf.components.ellipse(layer=(2, 0)))
e2 = c.add_ref(gf.components.ellipse(radii=(10, 6), layer=(2, 0))).movex(2)
e3 = c.add_ref(gf.components.ellipse(radii=(10, 4), layer=(2, 0))).movex(5)
c

/home/runner/work/gdsfactory/gdsfactory/gdsfactory/component.py:1684: UserWarning: Component 'Unnamed_c99626a4' contains 1 Unnamed cells
  warnings.warn(

Unnamed_c99626a4: uid c99626a4, ports [], references ['ellipse_1', 'ellipse_2', 'ellipse_3'], 0 polygons

c2 = gf.geometry.boolean(A=[e1, e3], B=e2, operation="A-B", layer=(2, 0))
c2

boolean_c5ebe741: uid 48f2b995, ports [], references [], 2 polygons

c = gf.Component("rectangle_with_label")
r = c << gf.components.rectangle(size=(1, 1))
r.x = 0
r.y = 0
c.add_label(
    text="Demo label",
    position=(0, 0),
    layer=(1, 0),
)
c

rectangle_with_label: uid 4a5f11ee, ports [], references ['rectangle_1'], 0 polygons

Move Reference by port

c = gf.Component("ref_port_sample")
mmi = c.add_ref(gf.components.mmi1x2())
bend = c.add_ref(gf.components.bend_circular(layer=(2, 0)))
c

ref_port_sample: uid 27a4d249, ports [], references ['mmi1x2_1', 'bend_circular_1'], 0 polygons

bend.connect("o1", mmi.ports["o2"])  # connects follow Source, destination syntax
c

ref_port_sample: uid 27a4d249, ports [], references ['mmi1x2_1', 'bend_circular_1'], 0 polygons

Mirror reference

By default the mirror works along the x=0 axis.

c = gf.Component("ref_mirror")
mmi = c.add_ref(gf.components.mmi1x2())
bend = c.add_ref(gf.components.bend_circular(layer=(2, 0)))
c

ref_mirror: uid 47268d7d, ports [], references ['mmi1x2_1', 'bend_circular_1'], 0 polygons

mmi.mirror()
c

ref_mirror: uid 47268d7d, ports [], references ['mmi1x2_1', 'bend_circular_1'], 0 polygons

Write GDS

GDSII is the Standard format for exchanging CMOS and Photonic circuits.

You can write your Component to GDS file.

c.write_gds("demo.gds")

2023-02-20 17:44:49.869 | INFO     | gdsfactory.component:_write_library:1704 - Wrote to 'demo.gds'

PosixPath('demo.gds')

You can see the GDS file in Klayout viewer.

Sometimes you also want to save the GDS together with metadata (settings, port names, widths, locations …) in YAML

c.write_gds_with_metadata("demo.gds")

2023-02-20 17:44:49.878 | INFO     | gdsfactory.component:_write_library:1704 - Wrote to 'demo.gds'
2023-02-20 17:44:49.888 | INFO     | gdsfactory.component:write_gds_with_metadata:1799 - Write YAML metadata to 'demo.yml'

PosixPath('demo.gds')

based on phidl tutorial